Novel 6-alkoxy-2, 3-diaminopyridine couplers in which the amino radical in position 2 is a disubstituted amino radical, and use of these couplers for dyeing keratin fibres

ABSTRACT

The invention relates to a dye composition that is useful for dyeing keratin fibres, containing at least one oxidation base and at least one coupler of the 6-alkoxy-2,3-diaminopyridine type in which the amino radical in position 2 is a disubstituted amino radical, to the use of this composition for dyeing keratin fibres and to the dyeing process using this composition. The invention also relates to novel 6-alkoxy-2,3-diaminopyridine compounds that are useful as couplers.

The invention relates to a dye composition that is useful for dyeingkeratin fibres, containing at least one oxidation base and at least onecoupler of the 6-alkoxy-2,3-diaminopyridine type in which the aminoradical in position 2 is a disubstituted amino radical, to the use ofthis composition for dyeing keratin fibres and to the dyeing processusing this composition. The invention also relates to novel6-alkoxy-2,3-diaminopyridine compounds that are useful as couplers.

It is known practice to dye keratin fibres, and in particular humanhair, with dye compositions containing oxidation dye precursors, whichare generally known as oxidation bases, such as ortho- orpara-phenylenediamines, ortho- or para-aminophenols and heterocycliccouplers. These oxidation bases are colourless or weakly colouredcompounds which, when combined with oxidizing products, can give rise tocoloured compounds by a process of oxidative condensation.

It is also known that the shades obtained with these oxidation bases canbe varied by combining them with couplers or coloration modifiers, theseagents being chosen especially from aromatic meta-diamines,meta-aminophenols, meta-diphenols and certain heterocyclic compoundssuch as indole compounds.

The variety of molecules used as oxidation bases and couplers allows awide range of colours to be obtained.

The “permanent” coloration obtained by means of these oxidation dyesmust moreover satisfy a certain number of requirements. Thus, it musthave no toxicological drawback, it must allow shades to be obtained inthe desired strength, and it must show good fastness with respect toexternal agents such as light, bad weather, washing, permanent-waving,perspiration and rubbing.

The dyes must also allow white hair to be covered and, finally, theymust be as unselective as possible, ie they must produce the smallestpossible differences in coloration along the same keratin fibre, whichis generally-differently sensitized (ie damaged) between its end and itsroot.

Document FR 1 397 551 describes dye compositions containing oxidationdye precursors of the trisubstituted pyridine derivative type, each ofthe substituents possibly being a hydroxyl, alkoxy, amino or NR₁R₂radical with R₁ and R₂ representing a H, alkyl or aryl. The colorationis obtained either by oxidation in air or with an oxidizing mediumcontaining aqueous hydrogen peroxide solution at basic pH. On account ofthe high oxidizability of these pyridine precursors, the dyeing resultsobtained on the hair have a tendency to change over time by changingcolour, which turns out to be particularly unattractive.

Document DE 3 233 540 proposes hair dye compositions containing, ascoupler, 6-alkoxy-3-aminopyridine derivatives substituted in position 2with an NH₂ or NHR₃ radical with R₃═H, C₁-C₄ alkyl or C₂-C₄ hydroxyalkylin combination with standard oxidation bases. These compositions give,in the presence of certain bases such as para-phenylenediamine orpara-toluenediamine, dark blue shades that are unstable to light andthat lack strength and uniformity between the root and the end of thehairs.

Documents DE 4 115 148, FR 2 779 952, EP 728 464 and DE 199 36 442propose to combine particular pyridine-based couplers of this type withspecific oxidation bases such as pyrazolopyrimidine, para-aminophenol,pyrimidine or 4,5- or 3,4-diaminopyrazole bases.

However, none of these compositions make it possible to obtain strongcolorations in varied shades that are uniform from the root to the endof the hairs, that show little selectivity and particularly goodresistance, and that have good chromaticity.

This aim is achieved with the present invention, one subject of which isa dye composition comprising, in a medium that is suitable for dyeing,

-   -   at least one oxidation base, and    -   at least one 6-alkoxy-2,3-diaminopyridine coupler of formula (I)        or a corresponding addition salt thereof:        in which:    -   R₄ represents a linear or branched C₁-C₄ alkyl radical        optionally substituted with one or more hydroxyl, C₁-C₂ alkoxy        or NR₇R₈ radicals in which R₇ and R₈ are chosen from a hydrogen        atom, a C₁-C₄ alkyl, a C₂-C₆ (poly)hydroxyalkyl, a C₂-C₆        (poly)aminoalkyl or a C₂-C₆ aminohydroxyalkyl;    -   R₅ represents a linear or branched C₁-C₆ alkyl radical        optionally substituted with one or more radicals chosen from        C₁-C₂ alkoxy, hydroxyl, carboxyl, sulphonic (—SO₃H) or NR₉R₁₀        radicals; a 2-acylaminoethyl radical; a        2-(2-hydroxyethyloxy)ethyl radical;    -   R₆ represents a linear or branched C₁-C₆ alkyl radical        optionally substituted with one or more radicals chosen from        C₁-C₂ alkoxy, hydroxyl, carboxyl, sulphonic, NR′₉R′₁₀ or        acylamino radicals (RCONH— with R being a C₁-C₄ alkyl); a        2-(2-hydroxyethyloxy)ethyl radical;    -   R₉, R₁₀, R₉′ and R₁₀′ denote, independently of each other, a        hydrogen atom; a C₁-C₄ alkyl radical optionally substituted with        one or more hydroxyl, amino, monoalkylamino, dialkylamino,        alkoxy or acylamino radicals.

In the context of the present invention, the term “alkyl” means linearor branched radicals, for example methyl, ethyl, n-propyl, isopropyl,butyl, etc., cycloalkyl radicals such as cyclobutyl, cyclopentyl,cyclohexyl, diazepane radicals, etc. An alkoxy radical is a radicalalk-O, the alkyl radical having the definition given above.

By way of example, R₅ and R6 independently represent a methyl, ethyl,propyl, hydroxyethyl, for example 2-hydroxyethyl, aminoethyl, forexample 2-aminoethyl, carboxyethyl, for example 2-carboxyethyl,acylaminoethyl, hydroxypropyl, for example 2-hydroxypropyl or3-hydroxypropyl, aminopropyl, for example 3-aminopropyl,N,N-dimethylaminoethyl, for example 2-N,N-dimethylaminoethyl,N-methylaminoethyl, for example 2-N-methylaminoethyl,(2-hydroxyethylamino) ethyl or (2-hydroxyethyloxy)ethyl radical.

Preferably, R₅ represents a C₁-C₄ alkyl radical optionally substitutedwith one or more radicals chosen from hydroxyl, C₁-C₂ alkoxy, amino,C₁-C₂ (di)alkylamino, carboxyl, C₁-C₂ (di)hydroxyalkylamino or sulphonicradicals; a 2-acylaminoethyl radical; a 2-(2-hydroxyethyloxy)ethylradical. In particular, R₅ represents an alkyl radical or an alkylradical substituted with one or more radicals chosen from a hydroxyl,C₁-C₂ alkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl or C₁-C₂(di)hydroxyalkylamino; a 2-acylaminoethyl radical; a2-(2-hydroxyethyloxy)ethyl radical. According to one particularlypreferred embodiment, R₅ represents a methyl, ethyl, propyl,2-hydroxyethyl, 2-aminoethyl, 2-carboxyethyl, 2-acylaminoethyl,2-hydroxypropyl, 3-hydroxypropyl, 3-aminopropyl,2-N,N-dimethylaminoethyl, 2-N-methylaminoethyl,2-(2-hydroxyethylamino)ethyl or 2-(2-hydroxyethyloxy)ethyl radical.

According to one particular embodiment, R₆ represents a substitutedalkyl radical.

By way of example, R₆ represents a hydroxyethyl, aminoethyl,carboxyethyl, acylaminoethyl, hydroxypropyl, aminopropyl,N,N-dimethylaminoethyl, N-methylaminoethyl, (2-hydroxyethylamino)ethylor (2-hydroxyethyloxy)ethyl radical.

Preferably, R₆ represents a C₁-C₄ alkyl radical substituted with one ormore radicals chosen from hydroxyl, C₁-C₂ alkoxy, amino, C₁-C₂(di)alkylamino, carboxyl, acylamino, C₁-C₂ (di)hydroxyalkylamino orsulphonic radicals; a 2-(2-hydroxyethyloxy)ethyl radical, in particularR₆ is a C₁-C₄ alkyl radical substituted with one or more radicals chosenfrom a hydroxyl, C₁-C₂ alkoxy, amino, C₁-C₂ (di)alkylamino, carboxyl,acylamino or (di)hydroxyalkylamino; a 2-(2-hydroxyethyloxy)ethylradical.

According to one particularly preferred embodiment, R₆ represents a2-hydroxyethyl, 2-aminoethyl, 2-carboxyethyl, 2-acylaminoethyl,2-hydroxypropyl, 3-hydroxypropyl, 3-aminopropyl,2-N,N-dimethylaminoethyl, 2-N-methylaminoethyl,2-(2-hydroxyethylamino)ethyl or 2-(2-hydroxyethyloxy)ethyl radical.

In formula (I), R₄ preferably represents a C₁-C₄ alkyl radicaloptionally substituted with one or more hydroxyl or C₁-C₂ alkoxyradicals. Preferably, R₄ preferably represents a C₁-C₄ alkyl radical.

According to one particular embodiment, R₅ is an alkyl radical and R₆ isan alkyl radical substituted with one or more hydroxyl. According toanother embodiment, R₅ and R₆ represent an alkyl radical substitutedwith one or more hydroxyl.

The compounds of formula (I) are for example the compounds

2-[(3-amino-6-methoxy-2- pyridyl)methylamino]ethanol

2-[(3-amino-6-methoxy-2- pyridyl)butylamino]ethanol

2-[(3-amino-6-methoxy-2- pyridyl)(2- hydroxyethyl)amino]ethanol

3-[(3-amino-6-methoxy-2- pyridyl)methylamino]propane- 1,2-diol

6-methoxy-N2,N2-bis (2- methoxyethyl)pyridine-2,3- diamine

6-methoxy-N2-ethyl-N2- methylpyridine-2,3-diamine

6-methoxy-N2-methyl-N2- propylpyridine-2,3-diamine

6-methoxy-N2-butyl-N2- methylpyridine-2,3-diamine

6-methoxy-N2-(3-aminopropyl)- N2-methylpyridine-2,3-diamine

2-[(3-amino-6-methoxy-2- pyridyl)ethylamino]ethanol

6-methoxy-N2,N2- diisopropylpyridine-2,3-diamine

6-methoxy-N2,N2- dipropylpyridine-2,3-diamine

6-methoxy-N2-butyl-N2- ethylpyridine-2,3-diamine

6-methoxy-N2-(2-aminoethyl)- N2-isopropylpyridine-2,3- diamine

6-methoxy-N2-cyclohexyl-N2- methylpyridine-2,3-diamine

2-[(3-amino-6-methoxy-2- pyridyl)(3- aminopropyl)amino]ethanol

6-methoxy-N2-cyclohexyl-N-2- ethylpyridine-2,3-diamine

2-[(3-amino-6-methoxy-2- pyridyl)pentylamino]ethanol

2-[(3-amino-6-methoxy-2- pyridyl)cyclohexylamino]- ethanol

2-[(3-amino-6-methoxy-2- pyridyl)(2- aminoethyl)amino]ethanol

6-methoxy-N2-methyl-N2-(6- methylaminohexyl)pyridine-2,3- diamineand the addition salts thereof.

The oxidation dye composition of the present invention comprises one ormore oxidation bases conventionally used in oxidation dyeing. By way ofexample, these additional oxidation bases are chosen frompara-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols,bis-para-aminophenols, ortho-aminophenols and heterocyclic bases, andthe addition salts thereof.

Among the para-phenylenediamines that may be mentioned, for example, arepara-phenylenediamine, para-toluenediamine,2-chloro-para-phenylenediamine, 2,3-dimethyl-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,5-dimethyl-para-phenylenediamine, N,N-dimethyl-para-phenylenediamine,N,N-diethyl-para-phenylenediamine, N,N-dipropyl-para-phenylenediamine,4-amino-N,N-diethyl-3-methylaniline,N,N-bis(β-hydroxyethyl)-para-phenylenediamine,4-N,N-bis(β-hydroxyethyl)amino-2-methylaniline,4-N,N-bis(β-hydroxyethyl)amino-2-chloroaniline,2-β-hydroxyethyl-para-phenylenediamine, 2-fluoro-para-phenylenediamine,2-isopropyl-para-phenylenediamine,N-(β-hydroxypropyl)-para-phenylenediamine,2-hydroxymethyl-para-phenylenediamine,N,N-dimethyl-3-methyl-para-phenylenediamine,N-ethyl-N-(β-hydroxyethyl)-para-phenylenediamine,N-(β,γ-dihydroxypropyl)-para-phenylenediamine,N-(4′-aminophenyl)-para-phenylenediamine,N-phenyl-para-phenylenediamine,2-β-hydroxyethyloxy-para-phenylenediamine,2-β-acetylaminoethyloxy-para-phenylenediamine,N-(β-methoxyethyl)-para-phenylenediamine, 4-aminophenylpyrrolidine,2-thienyl-para-phenylenediamine, 2-β-hydroxyethylamino-5-aminotolueneand 3-hydroxy-1-(4′-aminophenyl)pyrrolidine, and the addition saltsthereof with an acid.

Among the para-phenylenediamines mentioned above, para-phenylenediamine,para-toluenediamine, 2-isopropyl-para-phenylenediamine,2-β-hydroxyethyl-para-phenylenediamine,2-p-hydroxyethyloxy-para-phenylenediamine,2,6-dimethyl-para-phenylenediamine, 2,6-diethyl-para-phenylenediamine,2,3-dimethyl-para-phenylenediamine,N,N-bis-(β-hydroxyethyl)-para-phenylenediamine,2-chloro-para-phenylenediamine and2-β-acetylaminoethyloxy-para-phenylenediamine, and the addition saltsthereof with an acid, are particularly preferred.

Among the bis(phenyl)alkylenediamines that may be mentioned, forexample, areN,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)-1,3-diaminopropanol,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4′-aminophenyl)ethylenediamine,N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(β-hydroxyethyl)-N,N′-bis(4-aminophenyl)tetramethylenediamine,N,N′-bis(4-methylaminophenyl)tetramethylenediamine,N,N′-bis(ethyl)-N,N′-bis(4′-amino-3′-methylphenyl)ethylenediamine and1,8-bis(2,5-diaminophenoxy)-3,6-dioxaoctane, and the addition saltsthereof with an acid.

Among the para-aminophenols that may be mentioned, for example, arepara-aminophenol, 4-amino-3-methylphenol, 4-amino-3-fluorophenol,4-amino-3-hydroxymethylphenol, 4-amino-2-methylphenol,4-amino-2-hydroxymethylphenol, 4-amino-2-methoxymethylphenol,4-amino-2-aminomethylphenol, 4-amino-2-(β-hydroxyethylaminomethyl)phenoland 4-amino-2-fluorophenol, and the addition salts thereof with an acid.

Among the ortho-aminophenols that may be mentioned, for example, are2-aminophenol, 2-amino-5-methylphenol, 2-amino-6-methylphenol and5-acetamido-2-aminophenol, and the addition salts thereof with an acid.

Among the heterocyclic bases that may be mentioned, for example, arepyridine derivatives, pyrimidine derivatives and pyrazole derivatives.

Among the pyridine derivatives that may be mentioned are the compoundsdescribed, for example, in patents GB 1 026 978 and GB 1 153 196, forinstance 2,5-diaminopyridine, 2-(4-methoxyphenyl)amino-3-aminopyridine,2,3-diamino-6-methoxypyridine,2-(β-methoxyethyl)amino-3-amino-6-methoxypyridine and3,4-diaminopyridine, and the addition salts thereof with an acid.

Other pyridine oxidation bases that are useful in the present inventionare the 3-aminopyrazolo[1,5-a]pyridine oxidation bases or addition saltsthereof described, for example, in patent application FR 2 801 308.Examples that may be mentioned include pyrazolo[1,5-a]pyrid-3-ylamine,2-acetylaminopyrazolo[1,5-a]pyrid-3-ylamine,2-morpholin-4-ylpyrazolo[1,5-a]pyrid-3-ylamine,3-aminopyrazolo[1,5-a]pyridine-2-carboxylic acid,2-methoxypyrazolo[1,5-a]pyrid-3-ylamino,(3-aminopyrazolo[1,5-a]pyrid-7-yl)methanol,2-(3-aminopyrazolo[1,5-a]pyrid-5-yl)ethanol,2-(3-aminopyrazolo[1,5-a]pyrid-7-yl)ethanol,(3-aminopyrazolo[1,5-a]pyrid-2-yl)methanol,3,6-diaminopyrazolo[1,5-a]pyridine, 3,4-diaminopyrazolo[1,5-a]pyridine,pyrazolo[1,5-a]pyridine-3,7-diamine,7-morpholin-4-ylpyrazolo[1,5-a]pyrid-3-ylamine,pyrazol[1,5-a]pyridine-3,5-diamine,5-morpholin-4-ylpyrazolo[1,5-a]pyrid-3-ylamine,2-[(3-aminopyrazolo[1,5-a]pyrid-5-yl)(2-hydroxyethyl)amino]ethanol,2-[(3-aminopyrazolo[1,5-a]pyrid-7-yl)(2-hydroxyethyl)amino]ethanol,3-aminopyrazolo[1,5-a]pyridin-5-ol, 3-aminopyrazolo[1,5-a]pyridin-4-ol,3-aminopyrazolo[1,5-a]pyridin-6-ol and3-aminopyrazolo[1,5-a]pyridin-7-ol, and the addition salts thereof withan acid or with a base.

Among the pyrimidine derivatives that may be mentioned are the compoundsdescribed, for example, in patents DE 2 359 399; JP 88-169 571; JP05-63124; EP 0 770 375 or patent application WO 96/15765, for instance2,4,5,6-tetraaminopyrimidine, 4-hydroxy-2,5,6-triaminopyrimidine,2-hydroxy-4,5,6-triaminopyrimidine, 2,4-dihydroxy-5,6-diaminopyrimidineand 2,5,6-triaminopyrimidine, pyrazolopyrimidine derivatives such asthose mentioned in patent application FR-A-2 750 048, and among whichmention may be made of pyrazolo[1,5-a]pyrimidine-3,7-diamine,2,5-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,pyrazolo[1,5-a]pyrimidine-3,5-diamine,2,7-dimethylpyrazolo[1,5-a]pyrimidine-3,5-diamine,3-aminopyrazolo[1,5-a]pyrimidin-7-ol,3-aminopyrazolo[1,5-a]pyrimidin-5-ol,2-(3-aminopyrazolo[1,5-a]pyrimidin-7-ylamino)ethanol,2-(7-aminopyrazolo[1,5-a]pyrimidin-3-ylamino)ethanol,2-[(3-aminopyrazolo[1,5-a]pyrimidin-7-yl)(2-hydroxyethyl)amino]ethanol,2-[(7-aminopyrazolo[1,5-a]pyrimidin-3-yl)(2-hydroxyethyl)amino]ethanol,5,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,6-dimethylpyrazolo[1,5-a]pyrimidine-3,7-diamine,2,5,-N7,N7-tetramethylpyrazolo[1,5-a]pyrimidine-3,7-diamine and3-amino-5-methyl-7-imidazolylpropylaminopyrazolo[1,5-a]pyrimidine, andthe addition salts thereof with an acid, and the tautomeric formsthereof, when a tautomeric equilibrium exists.

Among the pyrazole derivatives that may be mentioned are the compoundsdescribed in patents DE 3 843 892 and DE 4 133 957, and patentapplications WO 94/08969, WO 94/08970, FR-A-2 733 749 and DE 195 43 988,for instance 4,5-diamino-1-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)pyrazole, 3,4-diaminopyrazole,4,5-diamino-1-(4′-chlorobenzyl)pyrazole,4,5-diamino-1,3-dimethylpyrazole, 4,5-diamino-3-methyl-1-phenylpyrazole,4,5-diamino-1-methyl-3-phenylpyrazole,4-amino-1,3-dimethyl-5-hydrazinopyrazole,1-benzyl-4,5-diamino-3-methylpyrazole,4,5-diamino-3-tert-butyl-1-methylpyrazole,4,5-diamino-1-tert-butyl-3-methylpyrazole,4,5-diamino-1-(β-hydroxyethyl)-3-methylpyrazole,4,5-diamino-1-ethyl-3-methylpyrazole,4,5-diamino-1-ethyl-3-(4′-methoxyphenyl)pyrazole,4,5-diamino-l-ethyl-3-hydroxymethylpyrazole,4,5-diamino-3-hydroxymethyl-1-methylpyrazole,4,5-diamino-3-hydroxymethyl-1-isopropylpyrazole,4,5-diamino-3-methyl-1-isopropylpyrazole,4-amino-5-(2′-aminoethyl)amino-1,3-dimethylpyrazole,3,4,5-triaminopyrazole, 1-methyl-3,4,5-triaminopyrazole,3,5-diamino-1-methyl-4-methylaminopyrazole and3,5-diamino-4-(β-hydroxyethyl)amino-1-methylpyrazole, and the additionsalts thereof with an acid.

The oxidation base(s) present in the composition of the invention is(are) each generally present in an amount of between 0.001% and 10% byweight approximately, and preferably between 0.005% and 6%, relative tothe total weight of the dye composition.

The composition according to the invention may contain one or moreadditional conventional couplers other than the coupler of formula (I).Among these additional couplers that may especially be mentioned aremeta-phenylenediamines, meta-aminophenols, meta-diphenols,naphthalene-based couplers and heterocyclic couplers other than thecouplers described above, and the addition salts thereof.

Examples that may be mentioned include 2-methyl-5-aminophenol,5-N-(β-hydroxyethyl)amino-2-methylphenol,6-chloro-2-methyl-5-aminophenol, 3-aminophenol, 1,3-dihydroxybenzene,1,3-dihydroxy-2-methylbenzene, 4-chloro-1,3-dihydroxybenzene,2,4-diamino-1-(β-hydroxyethyloxy)benzene,2-amino-4-(β-hydroxyethylamino)-1-methoxybenzene, 1,3-diaminobenzene,1,3-bis(2,4-diaminophenoxy)propane, 3-ureidoaniline,3-ureido-1-dimethylaminobenzene, sesamol,1-β-hydroxyethylamino-3,4-methylenedioxybenzene, α-naphthol,2-methyl-1-naphthol, 6-hydroxyindole, 4-hydroxyindole,4-hydroxy-N-methylindole, 2-amino-3-hydroxypyridine,6-hydroxybenzomorpholine, 3,5-diamino-2,6-dimethoxypyridine,1-N-(β-hydroxyethyl)amino-3,4-methylenedioxybenzene and2,6-bis(β-hydroxyethylamino)toluene, and the addition salts thereof withan acid.

In the composition of the present invention, the coupler(s) is (are)each generally present in an amount of between 0.001% and 10% by weightapproximately, and preferably between 0.005% and 6%, relative to thetotal weight of the dye composition.

In general, the addition salts of the oxidation bases and of thecouplers that may be used in the context of the invention are chosenespecially from the addition salts with an acid, such as thehydrochlorides, hydrobromides, sulphates, citrates, succinates,tartrates, lactates, tosylates, benzenesulphonates, phosphates andacetates, and the addition salts with a base, such as sodium hydroxide,potassium hydroxide, aqueous ammonia, amines or alkanolamines.

The dye composition in accordance with the invention may also containone or more direct dyes that may be chosen especially from nitrobenzenedyes, azo direct dyes and methine direct dyes. These direct dyes may beof nonionic, anionic or cationic nature.

The dye composition of the present invention is particularly useful fordyeing keratin fibres, in particular human keratin fibres. In this case,the medium is a cosmetic medium that is suitable for dyeing thesefibres.

This medium that is suitable for dyeing, also known as a dye support,generally consists of water or of a mixture of water and of at least oneorganic solvent to dissolve the compounds that would not be sufficientlysoluble in the water. Examples of organic solvents that may be mentionedinclude C₁-C₄ lower alkanols, such as ethanol and isopropanol; polyolsand polyol ethers, for instance 2-butoxyethanol, propylene glycol,propylene glycol monomethyl ether, diethylene glycol monoethyl ether andmonomethyl ether, and also aromatic alcohols, for instance benzylalcohol or phenoxyethanol, and mixtures thereof.

The solvents are preferably present in proportions preferably of between1% and 40% by weight approximately and even more preferably between 5%and 30% by weight approximately relative to the total weight of the dyecomposition.

The dye composition in accordance with the invention may also containvarious adjuvants conventionally used in hair dye compositions, such asanionic, cationic, nonionic, amphoteric or zwitterionic surfactants ormixtures thereof, anionic, cationic, nonionic, amphoteric orzwitterionic polymers or mixtures thereof, mineral or organicthickeners, and in particular anionic, cationic, nonionic and amphotericpolymeric associative thickeners, antioxidants, penetrating agents,sequestering agents, fragrances, buffers, dispersants, conditioners, forinstance volatile or non-volatile, modified or unmodified silicones,film-forming agents, ceramides, preserving agents and opacifiers.

The above adjuvants are generally present in an amount for each ofbetween 0.01%. and 20% by weight relative to the weight of thecomposition.

Needless to say, a person skilled in the art will take care to selectthis or these additional optional compound(s) such that the advantageousproperties intrinsically associated with the oxidation dye compositionin accordance with the invention are not, or are not substantially,adversely affected by the envisaged addition(s).

The pH of the dye composition in accordance with the invention isgenerally between 3 and 12 approximately and preferably between 5 and 11approximately. It may be adjusted to the desired value by means ofacidifying or basifying agents usually used for dyeing keratin fibres,or alternatively using standard buffer systems.

Among the acidifying agents that may be mentioned, for example, aremineral or organic acids, for instance hydrochloric acid,orthophosphoric acid, sulphuric acid, carboxylic acids, for instanceacetic acid, tartaric acid, citric acid or lactic acid, and sulphonicacids.

Among the basifying agents that may be mentioned, for example, areaqueous ammonia, alkaline carbonates, alkanolamines such asmonoethanolamine, diethanolamine and triethanolamine and derivativesthereof, sodium hydroxide, potassium hydroxide and the compounds offormula (II) below:

in which W is a propylene residue optionally substituted with a hydroxylgroup or a C₁-C₄ alkyl radical; R_(a), R_(b), R_(c) and R_(d), which maybe identical or different, represent a hydrogen atom or a C₁-C₄ alkyl orC₁-C₄ hydroxyalkyl radical.

The dye composition according to the invention may be in various forms,such as in the form of liquids, creams or gels, or in any other formthat is suitable for dyeing keratin fibres, and especially human hair.

The process of the present invention is a process in which thecomposition according to the present invention as defined above isapplied to the fibres, in the presence of an oxidizing agent, for a timethat is sufficient to develop the desired coloration. The colour mayrevealed at acidic, neutral or alkaline pH and the oxidizing agent maybe added to the composition of the invention just at the time of use, orit may be introduced using an oxidizing composition containing it,applied simultaneously with or sequentially to the composition of theinvention.

According to one particular embodiment, the composition according to thepresent invention is mixed, preferably at the time of use, with acomposition containing, in a medium that is suitable for dyeing, atleast one oxidizing agent, this oxidizing agent being present in anamount that is sufficient to develop a coloration. The mixture obtainedis then applied to the keratin fibres. After a leave-in time of 3 to 50minutes approximately and preferably 5 to 30 minutes approximately, thekeratin fibres are rinsed, washed with shampoo, rinsed again and thendried.

The oxidizing agents conventionally used for the oxidation dyeing ofkeratin fibres are, for example, hydrogen peroxide, urea peroxide,alkali metal bromates, persalts such as perborates and persulphates,peracids, and oxidase enzymes, among which mention may be made ofperoxidases, 2-electron oxidoreductases such as uricases, and 4-electronoxygenases, for instance laccases. Hydrogen peroxide is particularlypreferred.

The oxidizing composition may also contain various adjuvantsconventionally used in hair dye compositions and as defined above.

The pH of the oxidizing composition containing the oxidizing agent issuch that, after mixing with the dye composition, the pH of theresulting composition applied to the keratin fibres preferably rangesbetween 3 and 12 approximately and even more preferably between 5 and11. It may be adjusted to the desired value by means of acidifying orbasifying agents usually used in the dyeing of keratin fibres and asdefined above.

The ready-to-use composition that is finally applied to the keratinfibres may be in various forms, such as in the form of liquids, creamsor gels, or in any other form that is suitable for dyeing keratinfibres, and especially human hair.

The composition of the invention may be in the form of a kit. Such a kitcomprises a composition as defined above on the one hand, and anoxidizing composition on the other hand.

A subject of the invention is also a multi-compartment device, in whicha first compartment contains the dye composition of the presentinvention defined above and a second compartment contains an oxidizingagent. This device may be equipped with a means for applying the desiredmixture to the hair, such as the devices described in patent FR 2 586913 in the name of the Applicant.

Using this device, it is possible to dye keratin fibres using a processthat involves mixing a dye composition of the invention with anoxidizing agent, and applying the mixture obtained to the keratin fibresfor a time that is sufficient to develop the desired coloration.

Finally, a subject of the present invention is the6-alkoxy-2,3-diaminopyridine compounds of formula (I), and thecorresponding addition salts thereof as defined above, with theexception of2-(N-methyl-N-(β-hydroxyethyl)amino)-3-amino-6-methoxypyridine.

These compounds may be synthesized according to the following syntheticscheme:

The first step consists in reacting a 6-alkoxy-3-nitro-2-halopyridinederivative with an amine of the type HNR₅R₆ in which R₅ and R₆ have thesame meanings given above, in a polar solvent with a boiling point ofbetween 70° C. and 180° C. The reaction temperature varies, according tothe pyridine derivatives and the nucleophilic amine, from 75° C. to 140°C. The solvent that will be chosen is preferably alcohols such asethanol, isopropanol, butanol or pentanol, and also acetic acid, formicacid, dioxane or DMF.

The second step is a reduction reaction performed either byhydrogenation under heterogeneous catalysis, or by hydrogen transfer, oralternatively with metal hydrides or-with a formic acid/acetic acidcouple in the presence of palladium.

For example, the method, widely illustrated in the literature, ofhydrogenation catalyzed with palladium(0), Pd (II) or Raney nickel orPtO₂, is used.

The hydrogen-transfer reduction by reacting cyclohexene in the presenceof palladium is also found to be very effective.

The examples that follow serve to illustrate the invention without,however, being limiting in nature.

EXAMPLES OF SYNTHESIS EXAMPLE 12-[(3-Amino-6-methoxy-2-pyridyl)methyl-amino]ethanol

A) Synthesis of 2-[(6-methoxy-3-nitro-2-pyridyl)methyl-amino]ethanol

1.9 g (0.01 mol) of the product 2-chloro-3-nitro-6-methoxypyridine, 30ml of dioxane, 5 ml of water and 1.6 ml (0.02 mol) of2-methylaminoethanol are placed in a fully equipped round-bottomedflask. The mixture is refluxed for 2 hours with stirring and is thenpoured onto an ice/water mixture with stirring. The precipitate formedis filtered off by suction and dried under vacuum to constant weight.1.6 g of yellow powder are obtained, ie a yield of 70%.

B) Synthesis of 2-[(3-amino-6-methoxy-2-pyridyl)methyl-amino]ethanol

1.6 g (0.007 mol) of the product2-[(6-methoxy-3-nitro-2-pyridyl)methylamino]ethanol synthesizedaccording to procedure (A) above, 15 ml of ethanol, 5 ml of cyclohexeneand 0.5 g of palladium-on-charcoal are placed in a fully equippedround-bottomed flask. The mixture is refluxed for 2 hours with stirring,the catalyst is then removed by filtration and the filtrate is thenacidified with hydrochloric acid. After dilution with diisopropyl ether,the precipitate formed is filtered off by suction and dried under vacuumto constant weight. 2.0 g of powder are obtained, ie a yield of 100%.

Analysis by mass-spectrometry and magnetic resonance spectroscopy is inaccordance with the expected structure.

Weight analysis

Found: C 39.93 H 6.33 N 15.52 O 13.00 Cl 24.93

Calculated: C 40.01 H 6.34 N 15.55 O 11.84 Cl 26.25

EXAMPLE 2 2-[(3-Amino-6-methoxy-2-pyridyl)butylamino]-ethanol

A) Synthesis of 2-[butyl-(6-methoxy-3-nitro-2-pyridyl)amino]ethanol

1.9 g (0.01 mol) of the product 2-chloro-3-nitro-6-methoxypyridine, 30ml of dioxane, 5 ml of water and 2.62 ml (0.02 mol) of2-butylaminoethanol are placed in a fully equipped round-bottomed flask.The mixture is refluxed for 2 hours with stirring and is then pouredonto an ice/water mixture with stirring. The precipitate formed isfiltered off by suction and dried under vacuum to constant weight. 1.9 gof yellow powder are obtained, ie a yield of 70%.

B) Synthesis of 2-[(3-amino-6-methoxy-2-pyridyl)butyl-amino]ethanol

1.9 g (0.007 mol) of the product2-[butyl-(6-methoxy-3-nitro-2-pyridyl)amino]ethanol synthesizedaccording to procedure (A) above, 15 ml of ethanol, 5 ml of cyclohexeneand 0.5 g of palladium-on-charcoal are placed in a fully equippedround-bottomed flask. The mixture is refluxed for 2 hours with stirring,the catalyst is then removed by filtration and the filtrate is thenacidified with hydrochloric acid. After dilution with diisopropyl ether,the precipitate formed is filtered off by suction and dried under vacuumto constant weight. 1.63 g of powder are obtained, ie a yield of 84.5%.

Analysis by mass spectrometry and magnetic resonance spectroscopy is inaccordance with the expected structure.

EXAMPLE 3 2-[(3-Amino-6-methoxy-2-pyridyl)(2-hydroxy-ethyl)amino]ethanol

A) Synthesis of2-[(2-hydroxyethyl)(6-methoxy-3-nitro-2-pyridyl)amino]ethanol

1.9 g (0.01 mol) of the product 2-chloro-3-nitro-6-methoxypyridine, 30ml of dioxane, 5 ml of water and 2.1 ml (0.02 mol) of diethanolamine areplaced in a fully equipped round-bottomed flask. The mixture is refluxedfor 2 hours with stirring and is then poured onto an ice/water mixturewith stirring. The precipitate formed is filtered off by suction anddried. 1.9 g of yellow powder are obtained, ie a yield of 74%.

B) Synthesis of2-[(3-amino-6-methoxy-2-pyridyl)(2-hydroxyethyl)amino]ethanol

2 g (0.0078 mol) of the product2-[(2-hydroxyethyl)(6-methoxy-3-nitro-2-pyridyl)amino]ethanolsynthesized according to procedure (A) above, 15 ml of ethanol, 5 ml ofcyclohexene and 0.5 g of palladium-on-charcoal are placed in a fullyequipped round-bottomed flask. The mixture is refluxed for 2 hours withstirring, the catalyst is then removed by filtration and the filtrate isthen acidified with hydrochloric acid. After dilution with diisopropylether, the precipitate formed is filtered off by suction and dried undervacuum to constant weight. 2.21 g of powder are obtained, ie a yield of100%.

Analysis by mass spectrometry and magnetic resonance spectroscopy is inaccordance with the expected structure.

Weight analysis

Found: C 39.7 H 6.46 N 13.73 O 16.26 Cl 22.94

Calculated: C 40.01 H 6.38 N 14 O 15.99 Cl 23.62

EXAMPLE 4 3-[(3-Amino-6-methoxy-2-pyridyl)methyl-amino)propane-1,2-diol

A) Synthesis of3-[(6-methoxy-3-nitro-2-pyridyl)methyl-amino]propane-1,2-diol

4 g (0.0219 mol) of the product 2-chloro-3-nitro-6-methoxypyridine, 50ml of ethanol and 4.15 ml (0.0438 mol) of3-methylamino-1,2-dihydroxypropane are placed in a fully equippedround-bottomed flask. The mixture is refluxed for 2 hours with stirringand is then poured onto an ice/water mixture with stirring. Theprecipitate formed is filtered off by suction and dried under vacuum toconstant weight. 4.74 g of yellow powder are obtained, ie a yield of87.1%.

B) Synthesis of3-[(3-amino-6-methoxy-2-pyridyl)methylamino]propane-1,2-diol

4.65 g (0.018 mol) of the product3-[(6-methoxy-3-nitro-2-pyridyl)methylamino]propane-1,2-diol synthesizedaccording to procedure (A) above, 50 ml of ethanol, 10 ml of cyclohexeneand 2.1 g of palladium-on-charcoal are placed in a fully equippedround-bottomed flask. The mixture is refluxed for 2 hours with stirring,the catalyst is then removed by filtration and the filtrate is thenacidified with hydrochloric acid. After dilution with diisopropyl ether,the precipitate formed is filtered off by suction and dried under vacuumto constant weight. 4.33 g of powder are obtained, ie a yield of 91%.

Analysis by mass spectrometry and magnetic resonance spectroscopy is inaccordance with the expected structure.

Weight analysis:

Found: C 39.70 H 6.71 N 10.87 O 19.65

Calculated: C 40.01 H 6.38 N 14 O 15.99 Cl 23.62

EXAMPLE 5 6-Methoxy-N2,N2-bis(2-methoxyethyl)pyridine-2,3-diamine

A) Synthesis of bis(2-methoxyethyl)(6-methoxy-3-nitro-2-pyridyl)amine

4 g (0.0212 mol) of the product 2-chloro-3-nitro-6-methoxypyridine, 50ml of ethanol and 6.32 ml (0.0424 mol) of bis(2-methoxyethyl)amine areplaced in a fully equipped round-bottomed flask. The mixture is refluxedfor 2 hours with stirring and is then poured onto an ice/water mixturewith stirring. The precipitate formed is filtered off by suction anddried under vacuum to constant weight. 5.47 g of yellow powder areobtained, ie a yield of 90.6%.

B) Synthesis of 6-methoxy-N2,N2-bis(2-methoxyethyl)-pyridine-2,3-diamine

5.3 g (0.0186 mol) of the productbis(2-methoxyethyl)(6-methoxy-3-nitro-2-pyridyl)amine synthesizedaccording to procedure (A) above, 40 ml of ethanol, 15 ml of cyclohexeneand 2.3 g of palladium-on-charcoal are placed in a fully equippedround-bottomed flask. The mixture is refluxed for 2 hours with stirring,the catalyst is then removed by filtration and the filtrate is thenacidified with hydrochloric acid. After dilution with diisopropyl ether,the precipitate formed is filtered off by suction and dried under vacuumto constant weight. 4.96 g of powder are obtained, ie a yield of 91.3%.

Analysis by mass spectrometry and magnetic resonance spectroscopy is inaccordance with the expected structure.

Weight analysis: Found: C 47.6 H 7.36 N 13.7 O 17.85 Cl 13.45Calculated: C 46.53 H 7.81 N 13.56 O 20.66 Cl 11.44

EXAMPLES 6 to 21

The following 6-alkoxy-2,3-diaminopyridine compounds were obtainedaccording to the process described for Example 1B, starting with thenitro compounds indicated in the table below. 6-Alkoxy-2,3-diaminopyridine compounds according to Found Theoretical Nitro compoundsthe invention mass mass Ex.6

217 217.70 Ex.7

231 231.72 Ex.8

245 245.75 Ex.9

246 246.74 Ex.10

247 247.72 Ex.11

259 259.78 Ex.12

259 259.78 Ex.13

259 259.78 Ex.14

260 260.76 Ex.15

271 271.79 Ex.16

276 276.76 Ex.17

285 285.81 Ex.18

289 289.80 Ex.19

301 301.81 Ex.20

262 262.74 Ex.21

302 302.85

EXAMPLES OF DYEING EXAMPLE 1 Of Dyeing in Acidic Medium

The dye composition below was prepared: para-Phenylenediamine 5 × 10⁻³mol 2-[(3-Amino-6-methoxy-2- 5 × 10⁻³ mol pyridyl)butylamino]ethanol Dyesupport (*) Demineralized water qs 100 g(*) Dye support

96° ethanol 20 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units Na₂HPO₄ 0.28 g KH₂PO₄ 0.46 g

The composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). The pH ofthe final composition is equal to 7. The mixture obtained is applied tolocks of grey hair containing 90% white hairs. After a leave-in time of30 minutes, the locks are washed with a standard shampoo, rinsed andthen dried. Each lock is evaluated before and after dyeing in the L*a*b*system, using a Minolta® CM 2002 spectrocolorimeter (luminant D65).

In the L*a*b* space, the lightness is indicated by the value L* on ascale from 0 to 100, while the chromatic coordinates are expressed by a*and b*, which indicate two colour axes, a* the red-green axis, and b*the yellow-blue axis. According to this system, the higher the value ofL*, the lighter and weaker the colour. Conversely, the lower the valueof L*, the darker or stronger the colour.

The dyeing results below were obtained: Natural hair Permanent-wavedhair L* a* b* L* a* b* 16.44 2.03 −5.09 9.51 1.97 −2.97

EXAMPLES 2 to 7 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example2 3 4 5 6 7 6-Methoxy-N2-ethyl-N2-methylpyridine-2,3-diamine 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 4-Aminophenol 10⁻³ mol — —— — — Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]ethanol — — 10⁻³ mol — — —sulphate 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7-diamine — — — — 10⁻³mol — hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol hydrochloride — —— — — 10⁻³ mol Dye support (1) (*) (*) (*) (*) (*) (*) Demineralizedwater qs 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 2 3 4 5 6 7 Shadered- strong strong grey strong strong observed brown grey blue-greyviolet violet

EXAMPLES 8 to 11 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example8 9 10 11 6-Methoxy-N2-ethyl-N2- 10⁻³ 10⁻³ 10⁻³ 10⁻³propylpyridine-2,3-diamine mol mol mol mol Benzene-1,4-diamine 10⁻³ — —— hydrochloride mol 2-[(4-Aminophenyl)(2- — 10⁻³ — —hydroxyethyl)amino]ethanol mol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ —a]pyrimidine-3,7-diamine mol hydrochloride 2-(4,5-Diaminopyrazol-1- — —— 10⁻³ yl)ethanol hydrochloride mol Dye support (1) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 8 9 10 11 Shade red-brown red- Red observed brown violet

EXAMPLES 12 to 15 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example12 13 14 15 6-Methoxy-N2-butyl-N2- 10⁻³ 10⁻³ 10⁻³ 10⁻³methylpyridine-2,3-diamine mol mol mol mol Benzene-1,4-diamine 10⁻³ — —— hydrochloride mol 2-[(4-Aminophenyl)(2- — 10⁻³ — —hydroxyethyl)amino]ethanol mol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ —a]pyrimidine-3,7-diamine mol hydrochloride 2-(4,5-Diaminopyrazol-1- — —— 10⁻³ yl)ethanol hydrochloride mol Dye support (1) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontainng 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 12 13 14 15 Shadestrong grey strong red- observed brown violet brown

EXAMPLES 16 to 21 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example16 17 18 19 20 21 6-Methoxy-N2-(3-aminopropyl)-N2-methylpyridine-2,3-10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol diamine4-Aminophenol 10⁻³ mol — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]ethanol — —10⁻³ mol — — — sulphate 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — —10⁻³ mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7-diamine— — — — 10⁻³ mol — hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanolhydrochloride — — — — — 10⁻³ mol Dye support (1) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 16 17 18 19 20 21Shade orange- strong strong grey strong strong observed brownviolet-grey blue violet-grey violet

EXAMPLES 22 to 23 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example22 23 2-[(3-Amino-6-methoxy-2- 10⁻³ mol 10⁻³ molpyridyl)ethylamino]ethanol Benzene-1,4-diamine hydrochloride 10⁻³ mol —5-Methylpyrazolo[1,5-a]pyrimidine- — 10⁻³ mol 3,7-diamine hydrochlorideDye support (1) (*) (*) Demineralized water qs 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 22 23 Shade observedorange-brown red-violet

EXAMPLES 24 to 25 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example24 25 6-Methoxy-N2,N2-dipropylpyridine- 10⁻³ mol 10⁻³ mol 2,3-diamineBenzene-1,4-diamine hydrochloride 10⁻³ mol —5-Methylpyrazolo[1,5-a]pyrimidine- — 10⁻³ mol 3,7-diamine hydrochlorideDye support (1) (*) (*) Demineralized water qs 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 24 25 Shade observedred-brown red-brown

EXAMPLES 26 to 29 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example26 27 28 29 6-Methoxy-N2-butyl-N2- 10⁻³ 10⁻³ 10⁻³ 10⁻³ethylpyridine-2,3-diamine mol mol mol mol Benzene-1,4-diamine 10⁻³ — — —hydrochloride mol 2-[(4-Aminophenyl)(2- — 10⁻³ — —hydroxyethyl)amino]ethanol mol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ —a]pyrimidine-3,7-diamine mol hydrochloride 2-(4,5-Diaminopyrazol-1- — —— 10⁻³ yl)ethanol hydrochloride mol Dye support (1) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof .9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 26 27 28 29 Shadebrown grey strong red- observed violet grey

EXAMPLES 30 to 35 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example30 31 32 33 34 35 6-Methoxy-N2-(2-aminoethyl)-N2-isopropylpyridine- 10⁻³mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 2,3-diamine4-Aminophenol 10⁻³ mol — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]ethanol — —10⁻³ mol — — — sulphate 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — —10⁻³ mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7-diamine— — — — 10⁻³ mol — hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanolhydrochloride — — — — — 10⁻³ mol Dye support (1) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 30 31 32 33 34 35Shade orange strong strong yellow- strong strong observed greyblue-green brown violet- violet grey grey

EXAMPLES 36 to 39 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example36 37 38 39 6-Methoxy-N2-cyclohexyl-N2- 10⁻³ 10⁻³ 10⁻³ 10⁻³methylpyridine-2,3-diamine mol mol mol mol Benzene-1,4-diamine 10⁻³ — —— hydrochloride mol 2-[(4-Aminophenyl)(2- — 10⁻³ — —hydroxyethyl)amino]ethanol mol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ —a]pyrimidine-3,7-diamine mol hydrochloride 2-(4,5-Diaminopyrazol-1- — —— 10⁻³ yl)ethanol hydrochloride mol Dye support (1) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 36 37 38 39 Shadestrong grey strong red- observed red-brown violet-grey brown

EXAMPLES 40 to 42 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example40 41 42 6-Methoxy-N2-methyl-N2-(6- 10⁻³ mol 10⁻³ mol 10⁻³ molmethylaminohexyl)pyridine-2,3- diamine Benzene-1,4-diamine hydrochloride10⁻³ mol — — 2-[(4-Aminophenyl)(2- — 10⁻³ mol —hydroxyethyl)amino]ethanol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ mola]pyrimidine-3,7-diamine hydrochloride Dye support (1) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 40 41 42 Shadeobserved brown grey strong red-violet

EXAMPLES 43 to 46 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example43 44 45 46 2-[(3-Amino-6-methoxy-2- 10⁻³ 10⁻³ 10⁻³ 10⁻³pyridyl)pentylamino]ethanol mol mol mol mol Benzene-1,4-diamine 10⁻³ — —— hydrochloride mol 2-[(4-Aminophenyl)(2- — 10⁻³ — —hydroxyethyl)amino]ethanol mol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ —a]pyrimidine-3,7-diamine mol hydrochloride 2-(4,5-Diaminopyrazol-1- — —— 10⁻³ yl)ethanol hydrochloride mol Dye support (1) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% solution 0.23g AM Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AM acid asan aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous 3.6 gAM 60% solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammonia containing 20%NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 43 44 45 46 Shadebrown green- strong red- observed yellow red-violet brown grey grey

EXAMPLES 47 to 52 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example47 48 49 50 51 52 2-[(3-Amino-6-methoxy-2- 10⁻³ mol 10⁻³ mol 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol pyridyl)cyclohexylamino]ethanol 4-Aminophenol10⁻³ mol — — — — — Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]ethanol — — 10⁻³ mol — — —sulphate 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7-diamine — — — — 10⁻³mol — hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol hydrochloride — —— — — 10⁻³ mol Dye support (1) (*) (*) (*) (*) (*) (*) Demineralizedwater qs 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 47 48 49 50 51 52Shade red strong strong grey strong strong observed grey blue-greenviolet- violet grey grey

EXAMPLES 53 to 57 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example53 54 55 56 57 2-[(3-Amino-6-methoxy-2- 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³mol 10⁻³ mol pyridyl)(2-aminoethyl)- amino]ethanol 4-Aminophenol 10⁻³mol — — — — Benzene-1,4-diamine — 10⁻³ mol — — — hydrochloride2-[(4-Aminophenyl)(2- — — 10⁻³ mol — — hydroxyethyl)amino]ethanolsulphate 5-Methylpyrazolo[1,5- — — — 10⁻³ mol — a]pyrimidine-3,7-diaminehydrochloride 2-(4,5-Diaminopyrazol-1- — — — — 10⁻³ mol yl)ethanolhydrochloride Dye support (1) (*) (*) (*) (*) (*) Demineralized water qs100 g 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 53 54 55 56 57 Shadeorange strong blue-green strong violet- observed grey grey violet-greygrey

EXAMPLES 58 to 61 Of Dyeing in Alkaline Medium

The dye compositions were prepared in the following proportions: Example58 59 60 61 6-Methoxy-N2-cyclohexyl-N2- 10⁻³ 10⁻³ 10⁻³ 10⁻³ethylpyridine-2,3-diamine mol mol mol mol Benzene-1,4-diamine 10⁻³ — — —hydrochloride mol 2-[(4-Aminophenyl)(2- — 10⁻³ — —hydroxyethyl)amino]ethanol mol sulphate 5-Methylpyrazolo[1,5- — — 10⁻³ —a]pyrimidine-3,7-diamine mol hydrochloride 2-(4,5-Diaminopyrazol-1- — —— 10⁻³ yl)ethanol hydrochloride mol Dye support (1) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g(*) Dye support(1) pH 9.5

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution C₈-C₁₀ alkyl polyglucoside as an aqueous3.6 g AM 60% solution Benzyl alcohol 2.0 g Polyethylene glycolcontaining 8 ethylene 3.0 g oxide units NH₄Cl 4.32 g Aqueous ammoniacontaining 20% NH₃ 3.2 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 9.5 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 58 59 60 61 Shadered- brown red- red observed brown grey

EXAMPLES 62 to 68 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example62 63 64 65 66 67 68 6-Methoxy-N2-ethyl-N2-methylpyridine-2,3-diamine10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³mol — — — — ethanol sulphate Pyrimidine-2,4,5,6-tetraamine sulphate — —— 10⁻³ mol — — — 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — —10⁻³ mol — diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanolhydrochloride — — — — — — 10⁻³ mol Dye support (2) (*) (*) (*) (*) (*)(*) (*) Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 62 63 64 65 66 67 68Shade orange strong strong yellow- grey strong strong ob- brown greybrown grey brown served

EXAMPLES 69 to 75 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example69 70 71 72 73 74 75 6-Methoxy-N2-methyl-N2-propylpyridine-2,3-diamine10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]-ethanol — —10⁻³ mol — — — — sulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — —10⁻³ mol — — — 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol— — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7-diamine — — — —— 10⁻³ mol — hydrochloride 2-(4,5-Diaminopyrazol-1-yl) ethanol — — — — —— 10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 69 70 71 72 73 74 75Shade orange strong strong yellow strong strong strong ob- blue- blue-grey grey violet- served grey green grey

EXAMPLES 76 to 82 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example76 77 78 79 80 81 82 6-Methoxy-N2-butyl-N2-methylpyridine-2,3- 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol diamine4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³mol — — — — ethanol sulphate Pyrimidine-2,4,5,6-tetraamine sulphate — —— 10⁻³ mol — — — 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — —10⁻³ mol — diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — —— — — — 10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*)(*) Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 76 77 78 79 80 81 82Shade orange strong strong yellow- grey strong strong ob- blue- blue-brown violet- violet- served grey green grey grey

EXAMPLES 83 to 89 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example83 84 85 86 87 88 89 6-Methoxy-N2-(3-aminopropyl)-N2- 10⁻³ mol 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol methylpyridine-2,3-diamine4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³mol — — — — ethanol sulphate Pyrimidine-2,4,5,6-tetraamine sulphate — —— 10⁻³ mol — — — 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — —10⁻³ mol — diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl) ethanol — —— — — — 10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*)(*) Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 83 84 85 86 87 88 89Shade strong strong strong strong strong strong strong ob- yellow- greyblue- grey grey grey grey served brown grey

EXAMPLES 90 to 94 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example90 91 92 93 94 2-[(3-Amino-6-methoxy-2- 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³mol 10⁻³ mol pyridyl)ethylamino]ethanol Benzene-1,4-diamine 10⁻³ mol — —— — hydrochloride 2-[(4-Aminophenyl)(2- — 10⁻³ mol — — —hydroxyethyl)amino]ethanol sulphate 2-Ethyl-5-methyl-2H-pyrazole- — —10⁻³ mol — — 3,4-diamine hydrochloride 5-Methylpyrazolo[1,5- — — — 10⁻³mol — a]pyrimidine-3,7-diamine hydrochloride 2-(4,5-Diaminopyrazol-1- —— — — 10⁻³ mol yl)ethanol hydrochloride Dye support (2) (*) (*) (*) (*)(*) Demineralized water qs 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 90 91 92 93 94 Shadestrong blue- brown strong strong observed grey-blue green violet-greyviolet

EXAMPLES 95 to 99 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example95 96 97 98 99 6-Methoxy-N2,N2- 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³mol dipropylpyridine-2,3-diamine 4-Aminophenol 10⁻³ mol — — — —Benzene-1,4-diamine — 10⁻³ mol — — — hydrochloride 2-[(4-Aminophenyl)(2-— — 10⁻³ mol — — hydroxyethyl)amino]ethanol sulphate5-Methylpyrazolo[1,5- — — — 10⁻³ mol — a]pyrimidine-3,7-diaminehydrochloride 2-(4,5-Diaminopyrazol-1- — — — — 10⁻³ mol yl)ethanolhydrochloride Dye support (2) (*) (*) (*) (*) (*) Demineralized water qs100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 95 96 97 98 99 Shadeorange strong strong strong red observed grey blue-green violet-greygrey

EXAMPLES 100 to 106 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example100 101 102 103 104 105 106 6-Methoxy-N2-methyl-N2-(6- 10⁻³ mol 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ molmethylaminohexyl)pyridine-2,3-diamine 4-Aminophenol 10⁻³ mol — — — — — —Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — — ethanolsulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — — 10⁻³ mol — — —2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — — 10⁻³ mol— diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — —10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 100 101 102 103 104105 106 Shade orange strong strong yellow- grey strong strong ob- blue-blue- brown violet- violet- served grey green grey grey

EXAMPLES 107 to 113 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example107 108 109 110 111 112 113 6-Methoxy-N2-(2-aminoethyl)-N2- 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ molispropylpyridine-2,3-diamine 4-Aminophenol 10⁻³ mol — — — — — —Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — — ethanolsulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — — 10⁻³ mol — — —2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — — 10⁻³ mol— diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — —10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 107 108 109 110 111112 113 Shade strong strong strong Grey grey strong strong observedyellow- grey grey grey grey brown

EXAMPLES 114 to 120 Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example114 115 116 117 118 119 120 6-Methoxy-N2-cyclohexyl-N2-methylpyridine-10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol2,3-diamine 4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diaminehydrochloride — 10⁻³ mol — — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — — ethanolsulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — — 10⁻³ mol — — —2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — — 10⁻³ mol— diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — —10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 114 115 116 117 118119 120 Shade orange strong strong yellow- brown strong strong ob- greyblue- brown violet- violet- served green grey grey

EXAMPLES 121 to 127 Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example121 122 123 124 125 126 127 6-Methoxy-N2-benzyl-N2-methylpyridine-2,3-10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol diamine4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³mol — — — — ethanol sulphate Pyrimidine-2,4,5,6-tetraamine sulphate — —— 10⁻³ mol — — — 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — —10⁻³ mol — diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — —— — — — 10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*)(*) Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 121 122 123 124 125126 127 Shade or- strong strong strong strong strong strong ob- angeorange orange yellow yellow yellow- orange- served brown brown

EXAMPLES 128 to 134 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example128 129 130 131 132 133 134 6-Methoxy-N2-cyclohexyl-N2-ethylpyridine-10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol2,3-diamine 4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diaminehydrochloride — 10⁻³ mol — — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — — ethanolsulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — — 10⁻³ mol — — —2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — — 10⁻³ mol— diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — —10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 128 129 130 131 132133 134 Shade or- strong strong yellow- brown strong strong ob- angered- grey brown grey brown served brown

EXAMPLES 135 to 141 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example135 136 137 138 139 140 141 2-[(3-Amino-6-methoxy-2- 10⁻³ mol 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol pyridyl)pentylamino]ethanol4-Aminophenol 10⁻³ mol — — — — — — Benzene-1,4-diamine hydrochloride —10⁻³ mol — — — — — 2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³mol — — — — ethanol sulphate Pyrimidine-2,4,5,6-tetraamine sulphate — —— 10⁻³ mol — — — 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³mol — — hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — —10⁻³ mol — diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl) ethanol — —— — — — 10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*)(*) Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 135 136 137 138 139140 141 Shade yellow brown strong yellow- grey strong strong ob- blue-brown violet- violet- served green grey grey grey

EXAMPLES 142 to 148 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example142 143 144 145 146 147 148 2-[(3-Amino-6-methoxy-2- 10⁻³ mol 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ molpyridyl)cyclohexylamino]ethanol 4-Aminophenol 10⁻³ mol — — — — — —Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — — ethanolsulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — — 10⁻³ mol — — —2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — — 10⁻³ mol— diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — —10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 142 143 144 145 146147 148 Shade or- red- strong yellow- green- strong strong ob- angebrown grey brown yellow grey brown served grey

EXAMPLES 149 to 155 Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example149 150 151 152 153 154 155 2-[(3-Amino-6-methoxy-2-pyridyl)(2- 10⁻³ mol10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ molaminoethyl)amino]ethanol 4 -Aminophenol 10⁻³ mol — — — — — —Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — — ethanolsulphate Pyrimidine-2,4,5,6-tetraamine sulphate — — — 10⁻³ mol — — —2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7-diamine — — — — —10⁻³ mol — hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — —10⁻³ mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 149 150 151 152 153154 155 Shade orange- strong strong grey grey strong strong ob- browngrey blue- grey grey served grey

EXAMPLES 156 to 161 Of Dyeing in Acidic Medium

The dye compositions were prepared in the following proportions: Example156 157 158 159 160 161 6-Methoxy-N2-butyl-N2-ethylpyridine-2,3- 10⁻³mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol 10⁻³ mol diamine 4-Aminophenol10⁻³ mol — — — — — Benzene-1,4-diamine hydrochloride — 10⁻³ mol — — — —2-[(4-Aminophenyl)(2-hydroxyethyl)amino]- — — 10⁻³ mol — — — ethanolsulphate 2-Ethyl-5-methyl-2H-pyrazole-3,4-diamine — — — 10⁻³ mol — —hydrochloride 5-Methylpyrazolo[1,5-a]pyrimidine-3,7- — — — — 10⁻³ mol —diamine hydrochloride 2-(4,5-Diaminopyrazol-1-yl)ethanol — — — — — 10⁻³mol hydrochloride Dye support (2) (*) (*) (*) (*) (*) (*) (*)Demineralized water qs 100 g 100 g 100 g 100 g 100 g 100 g 100 g(*) Dye support(2) pH 7

96° ethanol 20.8 g Sodium metabisulphite as an aqueous 35% 0.23 g AMsolution Pentasodium salt of diethylenetriaminepentaacetic 0.48 g AMacid as an aqueous 40% solution Sodium metabisulphite as an aqueous 35%3.6 g AM solution Benzyl alcohol 2.0 g Polyethylene glycol containing 8ethylene 3.0 g oxide units KH₂PO₄ 0.28 g NaH₂PO₄ 0.47 g

Each composition is mixed at the time of use with an equal weight of20-volumes aqueous hydrogen peroxide solution (6% by weight). A final pHof 7 is obtained.

Each mixture obtained is applied to grey hair containing 90% whitehairs. After a leave-in time of 30 minutes, the hair is rinsed, washedwith a standard shampoo, rinsed again and then dried.

The following dyeing results were obtained. Example 156 157 158 159 160161 Shade orange- strong strong violet- strong strong observed brownblue- blue- grey violet- violet grey green grey

1-25. (canceled)
 26. A dye composition comprising, in a medium that issuitable for dyeing: at least one oxidation base, and at least one6-alkoxy-2,3-diaminopyridine coupler of formula (I), or at least oneaddition salt thereof:

wherein: R₄ is chosen from linear and branched C₁-C₄ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, and NR₇R₈ radicals wherein R₇ and R₈ are chosen fromhydrogen atoms, C₁-C₄ alkyl, C₂-C₆ (poly)hydroxyalkyl, C₂-C₆(poly)aminoalkyl, and C₂-C₆ aminohydroxyalkyl radicals; R₅ is chosenfrom linear and branched C₁-C₆ alkyl radicals optionally substitutedwith at least one radical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl,sulphonic (—SO₃H), and NR₉R₁₀ radicals; acylaminoethyl radicals; and2-(2-hydroxyethyloxy)ethyl radicals; and R₆ is chosen from linear andbranched C₁-C₆ alkyl radicals optionally substituted with at least oneradical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl, sulphonic,NR′₉R′₁₀, and acylamino radical, RCONH—, wherein R is a C₁-C₄ alkyl;wherein R₉, R₁₀, R′₉ and R′₁₀, which are independent of each other, arechosen from hydrogen atoms and C₁-C₄ alkyl radicals optionallysubstituted with at least one radical chosen from hydroxyl, amino,monoalkylamino, dialkylamino, alkoxy, and acylamino radicals.
 27. Thedye composition according to claim 26, wherein R₆ is chosen from asubstituted alkyl radical.
 28. The dye composition according to claim26, wherein R₅ and R₆, which are independent of each other, are chosenfrom C₁-C₄ alkyl radicals optionally substituted with at least oneradical chosen from hydroxyl, C₁-C₂ alkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl and C₁-C₂ (di)hydroxyalkylamino radicals; 2-acylaminoethylradicals; and 2-(2-hydroxyethyloxy)ethyl radicals.
 29. The dyecomposition according to claim 28, wherein R₅ is chosen from methyl,ethyl, propyl, 2-hydroxyethyl, 2-aminoethyl, 2-carboxyethyl,2-acylaminoethyl, 2-hydroxypropyl, 3-hydroxypropyl, 3-aminopropyl,2-N,N-dimethylaminoethyl, 2-N-methylaminoethyl,2-(2-hydroxyethylamino)ethyl, and 2-(2-hydroxyethyloxy)ethyl radicals.30. The dye composition according to claim 26, wherein R₆ is chosen fromC₁-C₄ alkyl radicals optionally substituted with at least one radicalchosen from hydroxyl, C₁-C₂ alkoxy, amino, C₁-C₂ (di)alkylamino,carboxyl, acylamino, and (di)hydroxyalkylamino radicals; and2-(2-hydroxyethyloxy)ethyl radicals.
 31. The dye composition accordingto claim 30, wherein R₆ is chosen from 2-hydroxyethyl, 2-aminoethyl,2-carboxyethyl, 2-acylaminoethyl, 2-hydroxypropyl, 3-hydroxypropyl,3-aminopropyl, 2-N,N-dimethylaminoethyl, 2-N-methylaminoethyl,2-(2-hydroxyethylamino)ethyl, and 2-(2-hydroxyethyloxy)ethyl radicals.32. The dye composition according to claim 26, wherein R₄ is chosen fromC₁-C₄ alkyl radicals optionally substituted with at least one radicalchosen from hydroxyl and C₁-C₂ alkoxy radicals.
 33. The dye compositionaccording to claim 32, wherein R₄ is chosen from C₁-C₄ alkyl radicals.34. The dye composition according to claim 33, wherein R₅ is an alkylradical and R₆ is an alkyl radical substituted with at least onehydroxyl.
 35. The dye composition according to claim 33, wherein R₅ andR₆ are chosen from alkyl radicals substituted with at least onehydroxyl.
 36. The dye composition according to claim 1, wherein thecompound of formula (I) is chosen from:2-[(3-amino-6-methoxy-2-pyridyl)methylamino]ethanol;2-[(3-amino-6-methoxy-2-pyridyl)butylamino]ethanol;2-[(3-amino-6-methoxy-2-pyridyl )(2-hydroxyethyl)amino]ethanol;3-[(3-amino-6-methoxy-2-pyridyl)methylamino]propane-1,2-diol;6-methoxy-N2,N2-bis(2-methoxyethyl)pyridine-2,3-diamine;6-methoxy-N2-ethyl-N2-methylpyridine-2,3-diamine;6-methoxy-N2-methyl-N2-propylpyridine-2,3-diamine;6-methoxy-N2-butyl-N2-methylpyridine-2,3-diamine;6-methoxy-N2-(3-aminopropyl)-N2-methylpyridine-2,3-diamine;2-[(3-amino-6-methoxy-2-pyridyl )ethylamino]ethanol;6-methoxy-N2,N2-diisopropylpyridine-2,3-diamine;6-methoxy-N2,N2-dipropylpyridine-2,3-diamine;6-methoxy-N2-butyl-N2-ethylpyridine-2,3-diamine;6-methoxy-N2-(2-aminoethyl)-N2-isopropylpyridine-2,3-diamine;6-methoxy-N2-cyclohexyl-N2-methylpyridine-2,3-diamine;2-[(3-amino-6-methoxy-2-pyridyl )(3-aminopropyl )amino]ethanol;6-methoxy-N2-cyclohexyl-N2-ethylpyridine-2,3-diamine;2-[(3-amino-6-methoxy-2-pyridyl)pentylamino]ethanol;2-[(3-amino-6-methoxy-2-pyridyl)cyclohexylamino]ethanol;2-[(3-amino-6-methoxy-2-pyridyl)(2-aminoethyl)amino]ethanol;6-methoxy-N2-methyl-N2-(6-methylaminohexyl)pyridine-2,3-diamine; and theaddition salts thereof.
 37. The dye composition according to claim 26,wherein the at least one oxidation base is chosen frompara-phenylenediamines, bis(phenyl)alkylenediamines, para-aminophenols,bis-para-aminophenols, ortho-aminophenols, heterocyclic bases, and theaddition salts thereof.
 38. The dye composition according to claim 26,wherein the at least one oxidation base is present in an amount rangingfrom 0.001% to 10% by weight, relative to the total weight of the dyecomposition, and wherein when more than one oxidation base is present,each oxidation base is present in said amount.
 39. The dye compositionaccording to claim 38, wherein the at least one oxidation base ispresent in an amount ranging from 0.005% to 6% by weight, relative tothe total weight of the dye composition.
 40. The dye compositionaccording to claim 26, further comprising at least one additionalcoupler chosen from meta-phenylenediamines, meta-aminophenols,meta-diphenols, naphthalene-based couplers heterocyclic couplers, andthe addition salts thereof, other than the at least one coupler offormula (I).
 41. The dye composition according to claim 40, wherein forthe at least one coupler of formula (I) and for the at least oneadditional coupler, if present, each coupler is present in the dyecomposition in an amount ranging from 0.001% to 10% by weight, relativeto the total weight of the dye composition.
 42. The dye compositionaccording to claim 41, wherein the at least one coupler of formula (I)and for the at least one additional coupler, if present, each coupler ispresent in the dye composition in an amount ranging from 0.005% to 6% byweight, relative to the total weight of the dye composition.
 43. The dyecomposition according to claim 26, wherein the dyeing medium is acosmetic medium that is suitable for dyeing keratin fibers.
 44. The dyecomposition according to claim 26, further comprising an oxidizingagent.
 45. A process for the oxidation dyeing of keratin fiberscomprising applying to the fibers, in the presence of an oxidizingagent, for a time that is sufficient to allow a desired color to beobtained, a dye composition comprising, in a medium that is suitable fordyeing: at least one oxidation base, and at least one6-alkoxy-2,3-diaminopyridine coupler of formula (I), or at least oneaddition salt thereof:

wherein: R₄ is chosen from linear and branched C₁-C₄ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, and NR₇R₈ radicals wherein R₇ and R₈ are chosen fromhydrogen atoms, C₁-C₄ alkyl, C₂-C₆ (poly)hydroxyalkyl, C₂-C₆(poly)aminoalkyl, and C₂-C₆ aminohydroxyalkyl radicals; R₅ is chosenfrom linear and branched C₁-C₆ alkyl radicals optionally substitutedwith at least one radical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl,sulphonic (—SO₃H), and NR₉R₁₀ radicals; acylaminoethyl radicals; and2-(2-hydroxyethyloxy)ethyl radicals; and R₆ is chosen from linear andbranched C₁-C₆ alkyl radicals optionally substituted with at least oneradical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl, sulphonic,NR′₉R′₁₀, and acylamino radical, RCONH—, wherein R is a C₁-C₄ alkyl;wherein R₉, R₁₀, R′₉and R′₁₀, which are independent of each other, arechosen from hydrogen atoms and C₁-C₄ alkyl radicals optionallysubstituted with at least one radical chosen from hydroxyl, amino,monoalkylamino, dialkylamino, alkoxy, and acylamino radicals.
 46. Theprocess according to claim 45, wherein the oxidizing agent is chosenfrom hydrogen peroxide, urea peroxide, alkali metal bromates, persalts,peracids, and oxidase enzymes.
 47. The process according to claims 45,wherein the oxidizing agent is mixed at the time of application with thedye composition.
 48. The process according to claim 18, wherein theoxidizing agent is applied to the fibers simultaneously with orsequentially to the dye composition.
 49. A multi-compartment kitcomprising a first dye compartment comprising a dye compositioncomprising, in a medium that is suitable for dyeing: at least oneoxidation base, and at least one 6-alkoxy-2,3-diaminopyridine coupler offormula (I), or at least one addition salt thereof:

wherein: R₄ is chosen from linear and branched C₁-C₄ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, and NR₇R₈ radicals wherein R₇ and R₈ are chosen fromhydrogen atoms, C₁-C₄ alkyl, C₂-C₆ (poly)hydroxyalkyl, C₂-C₆(poly)aminoalkyl, and C₂-C₆ aminohydroxyalkyl radicals; R₅ is chosenfrom linear and branched C₁-C₆ alkyl radicals optionally substitutedwith at least one radical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl,sulphonic (—SO₃H), and NR₉R₁₀ radicals; acylaminoethyl radicals; and2-(2-hydroxyethyloxy)ethyl radicals; and R₆ is chosen from linear andbranched C₁-C₆ alkyl radicals optionally substituted with at least oneradical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl, sulphonic,NR′₉R′₁₀, and acylamino radical, RCONH—, wherein R is a C₁-C₄ alkyl;wherein R₉, R₁₀, R′₉ and R′₁₀, which are independent of each other, arechosen from hydrogen atoms and C₁-C₄ alkyl radicals optionallysubstituted with at least one radical chosen from hydroxyl, amino,monoalkylamino, dialkylamino, alkoxy, and acylamino radicals; and atleast one second compartment comprising an oxidizing composition.
 50. A6-Alkoxy-2,3-diaminopyridine compound of formula (I) or an addition saltthereof:

wherein: R₄ is chosen from linear and branched C₁-C₄ alkyl radicalsoptionally substituted with at least one radical chosen from hydroxyl,C₁-C₂ alkoxy, and NR₇R₈ radicals wherein R₇ and R₈ are chosen fromhydrogen atoms, C₁-C₄ alkyl, C₂-C₆ (poly)hydroxyalkyl, C₂-C₆(poly)aminoalkyl, and C₂-C₆ aminohydroxyalkyl radicals; R₅ is chosenfrom linear and branched C₁-C₆ alkyl radicals optionally substitutedwith at least one radical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl,sulphonic (—SO₃H), and NR₉R₁₀ radicals; acylaminoethyl radicals; and2-(2-hydroxyethyloxy)ethyl radicals; and R₆ is chosen from linear andbranched C₁-C₆ alkyl radicals optionally substituted with at least oneradical chosen from C₁-C₂ alkoxy, hydroxyl, carboxyl, sulphonic,NR′₉R′₁₀, and acylamino radical, RCONH—, wherein R is a C₁-C₄ alkyl;wherein R₉, R₁₀, R′₉and R′₁₀, which are independent of each other, arechosen from hydrogen atoms and C₁-C₄ alkyl radicals optionallysubstituted with at least one radical chosen from hydroxyl, amino,monoalkylamino, dialkylamino, alkoxy, and acylamino radicals, whereinsaid compound of formula (I) is not2-(N-methyl-N-(D-hydroxyethyl)amino)-3-amino-6-methoxypyridine.